1. Field of the Invention
The present invention relates to a liquid cooling apparatus for integrated circuit chips, more particularly, to a cooling apparatus in which integrated circuit chips are cooled with cooling members in contact with the chips.
2. Description of the Related Art
An example of a cooling apparatus incorporating cooling members is disclosed in U.S. Pat. No. 5,023,695. In the structure shown in FIG. 3 of this patent, a cooling module 4 corresponds to the cooling member. The cooling module 4 is provided with a cavity 13. Cooling fluid is injected into the cavity 13.
In such cooling apparatus, the cooling member has to be in close contact with the integrated circuit chip. A gap between the cooling member and the integrated circuit chip decreases the cooling efficiency of the apparatus.
One of the factors preventing the contact of the cooling member and the integrated circuit chip is a difference in height between the integrated circuit chips. If an integrated circuit chip is low in height, the gap between the cooling member and the integrated circuit chip is wide. Another factor preventing the contact of the cooling member and the integrated circuit chip is inclination of the integrated circuit chip. If an integrated circuit chip is inclined, the cooling member contacts only partially with the integrated circuit chip. These factors can be eliminated by precisely adjusting the height and inclination of the cooling member.
However, when a plurality of integrated circuit chips are cooled, it is difficult to make the cooling members in close contact with the corresponding integrated circuit chips because the height and inclination of each integrated circuit chip is different. In the structure disclosed in U.S. Pat. No. 5,023,695, the cooling module 4 is composed of one member. For this reason, the cooling module 4 can not be adjusted to the height and inclination of each integrated circuit chip.
A cooling apparatus capable of solving such a problem is disclosed in U.S. Pat. No. 4,644,385. In the structure shown in FIG. 1 of the patent, the cooling member 1 is arranged independently to each of chips 2. The cooling members 1 are connected each other with pipes. In this structure, each cooling member 1 is closely contacted with the corresponding chip 2 regardless of the height and inclination of chip 2. Because the cooling members 1 are connected to each other through the bellows 12, the position and inclination of them can be changed freely. As a result, each of the cooling members 1 is brought in close contact with the corresponding chip 2.
As described in the second column, lines 56 to 60 of the patent, the bellows expands vertically due to the pressure of the coolant, so that the bellows applies pressure to the integrated circuit chip 2. If the supply of the coolant is increased, the pressure is also increased. High pressure of the coolant may destroy the integrated circuit chips 2 or joint portions between the integrated circuit chip 2 and circuit board 3. Therefore, the coolant cannot be adequately supplied in this structure.